Pyrotechnic sheet material consisting of one or more substrate layers of oxidizing polymeric film having a layer of oxidizable material on at least a portion of at least one surface of, the or each, substrate layer, the polymeric film and the oxidizable material being conjointly capable of reacting together exothermically on ignition, has been described in PCT International Publications Nos WO 90/10611 and WO 90/10724.
The use of pyrotechnic sheet material to ignite a propellant charge has been described in European patent application No 92300835-3 now European Patent publication No. 505024; and hybrid inflators containing gas heating elements comprising pyrotechnic sheet material have been described in United Kingdom patent application No 9302503.9now United Kingdom patent specification No. GB 2264772A.
Pyrotechnic sheet material for use in the gas-bag inflators of safety restraint systems are required to be very rapid acting and therefore the pyrotechnic material must have a high reaction rate.
An object of this invention is to provide a modified pyrotechnic sheet of the aforedescribed kind having an enhanced reaction rate and consequently enhanced rate and violence of burning and enhanced rate of energy release.